Crystalline gallophosphate compositions

ABSTRACT

A novel family of crystalline, microporous gallophosphate compositions is synthesized by hydrothermal crystallization at elevated temperatures from gallophosphate gels containing a molecular structure-forming template. The family comprises distinct species, each with a unique crystal structure. Calcination removed volatile extraneous matter from the intracrystalline void space and yields microporous crystalline adsorbents with pores, the dimensions of which vary, among the individual species, from about 3A to 10A in diameter. The compositions represent a new class of adsorbents of the molecular sieve type, and also exhibit properties somewhat analogous to zeolitic molecular sieves which render them useful as catalysts or catalyst based in chemical reactions such as hydrocarbon conversion.

This application is a division of prior U.S. application Ser. No.053,735, filed May 26, 1987, now U.S. Pat. No. 4,799,942, and which is adivision of application Ser. No. 811,282, filed Dec. 20, 1985, now U.S.Pat. No. 4,690,808.

The present invention relates in general to a novel family ofcrystalline gallophosphate compositions of the general formula GaPO₄ andto the method for their synthesis. More particularly it relates tocrystalline microporous gallophosphate compositions and to hydrothermalprocesses for preparing same.

Molecular sieves of the crystalline zeolite type are well known in theart and now comprise over 150 species of both naturally occurring andsynthetic compositions. In general the crystalline zeolites arealuminosilicates whose frameworks are formed from AlO₄ - and SiO₄tetrahedra joined by the sharing of oxygen atoms and characterized byhaving pore openings of uniform dimensions, having a significantion-exchange capacity and being capable of reversibly desorbing anadsorbed phase which is dispersed through the internal voids of thecrystal without displacing any atoms which make up the permanent crystalstructure.

Other crystalline microporous phases which are not zeolitic, i.e. do notcontain A10₄ - tetrahedra as essential framework constituents, but whichexnhibit the ion exchange and/or adsorption characteristics of thezeolitic phases are also known. Metallorganosilicates which are said topossess ion-exchange properties, have uniform pores and are capable ofreversibly adsorbing molecules having molecular diameters of about 6A orless are reported in U.S. Pat. No. 3,941,871 issued Mar. 2, 1976 toDwyer et al. Also a pure silica polymorph having molecular sievingproperties and a neutral framework containing no cations or cation sitesis defined in U.S. Pat. No. 4,061,724 issued Dec. 6, 1977 to R. W. Groseet al.

The chemistry of aluminum phosphates has been reviewed by J. H. Morriset al. (Chem. Soc. Rev., 6, 173 (1977)). The phosphates with an Al₂ O₃:P₂ O₅ molar ratio of 1:1 are the most common, and have been the mostwidely studied. Anhydrous AlPO₄ is isoelectronic and isostructural withsilica and exists in quartz (as berlinite), tridymite, and cristobaliteforms possessing frameworks of alternating AlO₄ and PO₄ tetrahedra. Inaddition to these, F. D.'Yvoire [Bull. Soc. Chim. France, 1762 (1961)]has described five anhydrous crystalline AlPO₄ forms which have nosilica analogs.

Two hydrates of AlPO₄ with the stoichiometry AlPO₄.2H₂ O, metavarisciteand variscite, occur in natural and synthetic forms. Their structureswere determined by Kniep and coworkers (Acta Crysta., B29, 2292 (1973);ibid., B33 263 (1977), and both can be described as frameworks ofalternating octahedral AlO₄ (H₂ O)₂ and tetrahedral PO₄ units. In boththe metavariscite and variscite structures the H₂ O is chemically boundto the Al and, although small amounts of this water can be removedreversibly, complete dehydration is irreversible and leads tosignificant structural changes and the formation of anhydrous AlPO₄phases.

In addition to these, six crystallographically unique, metastablehydrates have been synthesized by F. D'Yvoire (ibid.). Of these, fourare reported to be reversibly dehydrated under mild conditions to yieldanhydrous phases, but in each case significant changes in frameworktopology occurred. These changes were reported to be reversible byrehydration. It is possible therefore that the interaction between waterand these aluminophosphate phases results in chemical bonding, such asthe formation of AlO₄ (H₂ O₂)₂ octahedra, rather than physisorption.

The hydrothermal synthesis of aluminophosphates in the presence ofvarious alkali metal, alkaline earth, and NH₄ cations has been reportedby Haseman and coworkers (Soil Sci. Soc. Proceed., 76 (1950); Soil Sci.,70, 257-271 (1950)), by Cole and Jackson (J. Phys. Chem.), 54, 128-142(1950)), and by Golub and Boldog (Russ. Jour, Inorg, Chem., 21, 45(1976)). A variety of known minerals (e.g., palmierite, taranakite,wavellite, variscite) and many novel crystalline materials wereobtained. Virtually all of these materials had Al/P ratios differentfrom 1.0. Although most of the products had appreciable H₂ O contentonly one product was examined by X-ray powder diffraction afterdehydration. This product, taranakite, became amorphous at 125° C. Thestability of the other phases is unknown.

R. M. Barrer and D. J. Marshall (J. Chem. Soc., 616 (1965)) attempted tosubstitute P for Si during hydrothermal crystallization of mixedframeworks analogous to aluminosilicates. The crystalline productsobtained from synthesis mixtures containing sources of Al, Si, and Pwere predominately aluminosilicates (e.g., montmorillonite, analcite,and cancrinite) and phosphates (e.g., hydroxyapatite). Severalunidentified crystalline solids were observed, characterized solely bytheir X-ray powder diffraction patterns. Evidence for phosphorusincorporation in the aluminosilicate structures or silicon incorporationin the hydroxyapatites was not obtained, however.

G. Kuehl has used phosphate as a complexing ion for aluminum in thehydrothermal synthesis of certain zeolites (Proceedings of the LondonConf. on Molecular Sieves, April 1967, p. 85; Inorg. Chem., 10, 2488(1971)). Presumably the phosphate complexes some of the aluminum,lowering the effective concentration of the more reactivehydroxoaluminate species in the reaction mixture and, thereby, increasesthe ratio of silicate to hydroxoaluminate. The zeolite products had ahigher Si/Al ratio than normal and presumably no incorporation of P intothe zeolite frameworks was observed. In one case, a high-silica form ofzeolite A contained phosphate intercalcated in the sofalite cages.

In an attempt to isolate the aluminophosphate species formed whenphosphate is added to a zeolite synthesis mixture, G. Kuehl prepared thecrystalline compounds [(CH₃)₄ N]₃ [Al(PO₄)₂ ].sup. XH₂ O where X=10, 4,and 1.5. They were characterized by X-ray powder diffraction, thermal,and elemental analysis, and were described as salts containing isolatedAl(PO₄)₂ (OH₂)_(x) ³⁻ units. Removal of all the H₂ O caused thedecomposition of these compounds (U.S. Pat. No. 3,386,801 (1968); J.Inorg. Nucl. Chem., 31, 1943 (1969)).

U.S. Pat. No. 4,310,440 discloses a novel class of aluminophosphateshaving an essential crystalline framework structure whose chemicalcomposition expressed in terms of molar ratios of oxides, (anhydrousbasis) is

    Al.sub.2 O.sub.3 :1.0±0.2P.sub.2 O.sub.5

said framework structure being microporous in which the pores areuniform and in each species have nominal diameters within the range offrom 3 to 10 Angstroms; an intracrystalline adsorption capacity forwater at 4.6 torr and 24° C. of at least 3.5 weight percent, theadsorption of water being completely reversible while retaining the sameessential framework topology in both the hydrated and dehydrated state.

U.S. Pat. No. 4,440,871 discloses a novel class of crystallinemicroporous silicoaluminophosphates the pores of which are uniform andhave nominal diameters of greater than about 3 Angstroms and whoseessential empirical chemical composition in the as-synthesized andanhydrous form is

    mR: (Si.sub.x Al.sub.y P.sub.z).sub.2

wherein "R" represents at least one organic templating agent present inthe intracrystalline pore system; "m" has a value of from 0.02 to 0.3;"m" represents the moles of "R" present per mole of (Si_(x) Al_(y) P₂)₂; and "x", "y" and "z" represent the mole fractions of silicon, aluminumand phosphorus respectively, present as tetrahedral oxides.

Several reports of gallim substitutoion have been made. In Barrer, R.M., Baynham, J. W., Bultitude, F. W., and Meier, W. M., J. Chem. Soc.,(1959), 195-208, it is reported that Al was replacedwith Ga in Na gelsof the zeolite types. It was reported that a Na gallosilicate of thethompsonite-type zeolite was made and that Na gallogermanate analogs ofthompsonite, faujasite, sodalite, zeolites were made. In Tananaev, I. V.and N. N. Chudinova, Russian J. Inor. Chem. (9), (1964), 135-138, it wasreported that stoichiometric, precipitated, amorphous GaPO4 (+3H2O) wasmade from GaCl₃ and H₃ PO₄ or NaH2PO4. The products of a dehydration at80°-140° C. were amorphous and heating to 540° C. converted it to a lowcristobalite structure. Heating above 940° C. gave a high-cristobaliteintermediate, but 1000° C. heating and slow cooling to ambient gave aberlinite (quartz). In Selbin, J., and Mason, R. B., J. Inorg. Nucl.Chem., (1961), (20), 222-228, Ga,Si zeolites were prepared in a Nasystem including 13X, sodalite, and an unidentified phase. The 13Xanalog had molecular sieve properties, as measured by uptake ofn-heptane, while others did not. Also, a Ga,Al,Si (Na) analog of 13Xzeolite was reported and adsorption was confirmed by uptake ofn-heptane. In Mooney-Slater, R. C. L., (1966), Acta Cryst., (20),526-534, crystals were prepared of a hydrated gallium phosphate offormula GaPO₄ -2H₂ O which lost water between 100° and 370° C. afterwhich the product was found to be amorphous. The author reported anX-ray single crystal structure of GaPO₄ -2H₂ O and concluded it to be ahydrated basic salt in which the gallium is part of an infinite hydratedhydroxy chain complex rather than functioning as a single ion. In Pluth,J. J., Smith, J. V., Bennett, J. M., and Cohen, J. P., Acta Cryst.,(1984), (C40), 2008-2011, The crystal structure of NH₄ Al₂ (OH)(H₂O)(PO₄)2-H₂ O was reported and found it to be structurally related tothe GaPO₄ -2H₂ O of Mooney-Slater which appeared to have H₃ O and Ga inplace of the NH₄ and Al in the above formula. Structural relation to theK,Fe,PO₄ species, leucophosphate, was also shown. This hydratedNH₃,Al,PO₄ species, also referred to as AlPO₄ -15, first becomesamorphous then converts to a form of cristobalite upon heating to removethe NH₃ and water. In Eshchenko, L. S., Pechkovskii, V. V., andStanovaya, L. S., Inor. Materials (Russian), (14), (1978), 723-726,investigations were reported of an orthorhombic form of GaPO₄ -2H₂ Owhich found it structurally like the aluminophosphate hydrate denotedvariscite. Thermal analysis showed dehydration of the GaPO₄ -2H₂ O to becomplete by 190° C. They also found that heating to 190° C. or aboveresulted in conversion to the anhydrous quartz-like crystalline phase ofGaPO₄.

A recent report of gallium phosphate compositions may be found in "SomeGallium Phosphate Frameworks Related to the Aluminum Phosphate MolecularSieves: X-Ray Structural Characterization of {Pr--I--NH₃) [Ga₄(PO₄)₄.sup.· OH}.sup.· H₂ O", by John B. Parise, J. Chem. Soc., CHEM.COMMUN., pages 606-607 May 1, 1985. This report describes members of thegeneric class of gallophosphates of the instant invention.

DETAILED DESCRIPTION OF THE INVENTION

The novel class of gallophosphate compositions are characterized ashaving a crystalline framework structure whose chemical compositionexpressed in terms of molar ratios of oxides, is

    mR:Ga.sub.2 O.sub.3 :1.0±0.2P.sub.2 O.sub.5

wherein "R" represents at least one organic templating agent present inthe intracrystalline pore system; "m" has a value of from 0.02 to 0.3;"m" represents the moles of "R"; and said framework structure beingmicroporous in which the pores in each species have nominal diameterswithin the range of from 3 to 10 Angstroms. In one embodiment the GaPO₄compositions are calcined to remove at least some template "R" and theintracrystalline adsorption capacity for oxygen at 100 torr and -183° C.is at least 3 weight percent. The instant compositions may also becharacterized by their retaining at least 50 percent of theircrystallinity after calcination. The instant compositions retain atleast 50 percent of their original crystallinity, preferably at least 70percent and most preferably at least 80 percent of the crystallinity ofthe original starting method when calcined at temperatures above about300° C. for at least one hour.

The individual gallophosphate species of the instant invention may becharacterized by their x-ray diffraction patterns. The following x-raydiffraction patterns are representative of x-ray diffraction patternswhich may be characteristic of particular gallophosphate species:

                  TABLE A                                                         ______________________________________                                                                Relative                                              2.sup.θ  d(A)     Intensity                                             ______________________________________                                        8.1-8.3        10.9-10.6                                                                              VS                                                    9.6-9.9        9.2-9.0  VW-W                                                  10.4-10.6      8.52-8.38                                                                              VW-M                                                  15.1-15.4      5.88-5.77                                                                              VW-W                                                  21.8-22.0      4.08-4.03                                                                              VW-W                                                  22.4-22.7      3.97-3.92                                                                              VW-W                                                  ______________________________________                                    

                  TABLE B                                                         ______________________________________                                                              Relative                                                2.sup.θ  d(A)   Intensity                                               ______________________________________                                        7.4            12.0   VS                                                      18.2           4.85   W                                                       21.5           4.13   W                                                       22.3           3.99   W                                                       23.8           3.73   W                                                       29.2           3.06   W                                                       ______________________________________                                    

The present gallophosphates are prepared by hydrothermal crystallizationof a reaction mixture prepared by combining a reactive source ofphosphate, a gallium compound and water and at least onestructure-directing or templating agent which can include an organicamine and a quaternary ammonium salt. In the as-synthesized form thestructure-directing agent is contained within the framework structure ofthe gallophosphate in amounts which vary from species to species butusually does not exceed one mole per mole of Ga₂ O₃ thereof. Thisstructure-directing agent is readily removed by water washing orcalcination and does not appear to be an essential constituent of theproduct gallophosphate.

Broadly, the preparative process comprises forming a reactive mixturewhich in terms of molar ratios of oxides is

    Ga.sub.2 O.sub.3 :1±0.5P.sub.2 O.sub.5 :7-100H.sub.2 O

and containing an effective amount ot template preferably from about 0.2to 10.0 moles of templating agent per mole of Ga₂ O₃. It has beenobserved that the amount of template is related, at least in part, tothe gallium source. For example, the use of an acid salt of gallium mayenable the use of a higher effective amount of template to form theinstant gallophosphate compositions. The reaction mixture is placed in areaction vessel inert toward the reactin system and heated at atemperature of at least about 100° C., preferably between 100° C. and300° C., until crystallized, usually a period from 2 hours to 2 weeks.The solid crystalline reaction product is then recovered by anyconvenient method, such as filtration or centrifugation, washed withwater and dried at a temperature between ambient and 110° C. in air.

In a preferred crystallization method the source of phosphate isphosphoric acid, and source of gallium is gallium (III) hydroxide,gallium (III) sulfate, or other soluble gallium (III) salts, thetemperature is 125° C. to 200° C., and the crystallization time is fromone to seven days. The preferred ratio of oxides in the reaction mixtureis

    Ga.sub.2 O.sub.3 :0.8-1.2P.sub.2 O.sub.5 :25-75H.sub.2 O

in general the most preferred reaction mixture contains per mole of Ga₂O₃ from about 0.5-8.0 moles of templating agent, from 40-75 moles ofwater and about 1.0 mole of P₂ O₅.

Not all templating agents suitably employed in the preparation ofcertain species of gallophosphates of this invention are suitable forthe preparation of all members of the generic class. The relationship ofspecific templating agents to the individual product species is apparentfrom the illustrative Examples set forth hereinafter. The template maybe selected from the group consisting of tetrapropylammonium hydroxide;tetraethylammonium hydroxide; tripropylamine; triethylamine;triethanolamine; piperidine; cyclohexylamine; 2-methyl pyridine;N,N-dimethylbenzylamine; ethylenediamine; pyrrolidine;N,N-diethylethanolamine; dicyclohexylamine; N,N-dimethylethanolamine;choline; N,N dimethylpiperazine; 1,4-diazabicyclo(2,2,2)octane;N-methyldiethanolamine; N-methylethanolamine; N-methylpiperidine;3-methylpiperidine; N-methylcyclohexylamine; 3-methylpyridine;4-methylpyridine; quinuclidine; andN,N'-dimethyl-1,4-diazabicyclo(2,2,2)octane dihydroxide.

The most suitable phosphorus source is phosphoric acid, although organicphosphates and conventional phosphorus salts may be employed.

The gallium source may be a gallium (III) hydroxide, gallium alkoxides,gallium carboxylates (e.g., gallium oxalate and gallium acetate),gallium trioxide (Ga₂ O₃), gallium (III) sulfate or other suitablegallium sources, including organogallium compounds.

The method of preparation and the physical and chemical properties ofcertain members of the present class of novel gallophosphates areillustrated and characterized, respectively, in the following examples.The species compounds are denominated as GaPO₄ -n wherein "n" is a smallletter specific to each individual member as prepared herein.

EXAMPLE 1

(a) GaPO₄ -a was prepared by the following procedure: 6.5 grams ofgallium (III) sulfate hydrate (Ga₂ (SO₄)₃.12H₂ O) was dissolved in 6.5grams H₂ O and added to a solution containing 2.2 grams of quinuclidine(C₇ H₁₃ N) which was previously dissolved in 2.0 grams of H₂ O.Orthophosphoric acid (2.3 grams of 85% orthophosphoric acid (H₃ PO₄))was mixed into the initial mixture, followed by the addition of another4.4 grams of quinuclidine. The resulting mixture was blended to form afinal reaction mixture with a composition in terms of molar oxide ratiosof:

    6.0C.sub.7 H.sub.13 N:1.0Ga.sub.2 O.sub.3 :1.0P.sub.2 O.sub.5 :3.0H.sub.2 SO.sub.4 :64H.sub.2 O

A portion of the reaction mixture was placed in a sealed stainless steelpressure vessel lined with polytetrafluoroethylene and heated in an ovenat 200° C. for 24 hours. The solid product was recovered by filtration,water washed, and dried in air at room temperature. A small amount of animpurity was present in the solid product but the major component, GaPO₄-a, had an x-ray powder diffraction pattern characterized by thefollowing data (Table I):

                  TABLE I                                                         ______________________________________                                        2.sup.θ d(A)    (I/Io) × 100                                      ______________________________________                                        8.2           10.74   100                                                     9.8           9.07    2                                                       10.5          8.41    1                                                       13.4          6.62    1                                                       14.3          6.20    3                                                       15.2          5.83    1                                                       16.5          5.37    5                                                       17.3          5.12    3                                                       17.8          4.99    1                                                       19.6          4.53    2                                                       21.9          4.06    9                                                       22.5          3.95    5                                                       24.3          3.66    1                                                       24.8          3.58    4                                                       27.1          3.29    1                                                       28.8          3.10    5                                                       29.2          3.05    1                                                       30.0          2.98    2                                                       30.6          2.92    1                                                       31.8          2.81    2                                                       33.3          2.69    1                                                       33.8          2.66    4                                                       35.0          2.56    1                                                       36.4          2.468   1                                                       36.8          2.442   1                                                       37.1          2.426   1                                                       38.4          2.346   1                                                       39.9          2.262   1                                                       47.7          1.919   1                                                       48.3          1.883   1                                                       50.0          1.825   1                                                       51.2          1.784   1                                                       51.7          1.768   1                                                       53.2          1.722   1                                                       54.4          1.688   1                                                       ______________________________________                                    

(b) Another portion of the reaction mixture from part (a) above washeated at 150° C. for 24 hours and the solid product isolated in asimilar manner. Again the solid was predominanately GaPO₄ -a with anx-ray powder diffraction pattern essentially as set forth above in TableI. By chemical analysis the product composition was 37.4 wt.% P₂ O₅, 47wt.% Ga₂ O₃, 9.5 wt.% Carbon, 1.4 wt.% Nitrogen, and 15.7 wt.% LOI (LossOn Ignition), corresponding to a molar oxide ratio product compositionof:

    0.43C.sub.7 H.sub.13 N:0.95Ga.sub.2 O.sub.3 :1.00P.sub.2 O.sub.5 :0.66H.sub.2 O

which corresponds to the formula (anhydrous basis):

    0.11(C.sub.7 H.sub.13 N)(Ga.sub.0.49 P.sub.0.51)O.sub.2

(c) A portion of the solid product from part (b) above was activatedunder vacuum at 425° C. for 2 hours in a standard McBain-Bakrgravimetric adsorption apparatus and the following adsorption data wereobtained (an additional 350° C. activation of the sample followed eachadsorbate):

    ______________________________________                                                 Kinetic     Pressure, Temp.,                                                                              Wt. %                                    Adsorbate                                                                              Diameter, (A)                                                                             (Torr)    (°C.)                                                                        Adsorbed                                 ______________________________________                                        O.sub.2  3.46        102       -183  11.7                                     O.sub.2  3.46        698       -183  12.3                                     n-hexane 4.3         44        23    4.2                                      isobutane                                                                              5.0         501       22    0.2                                      H.sub.2 O                                                                              2.65        4.6       23    13.7                                     H.sub.2 O                                                                              2.65        19.6      23    17.0                                     ______________________________________                                    

The adsorption of n-hexane and the essentially nil adsorption ofisobutane show the pore size of the product to be at least 4.3 Å andless than 5.0 Å.

EXAMPLE 2

(a) In another preparation of GaPO₄ -a, gallium (III) hydroxide wasadded to a solution consisting of tetramethylammonium hydroxidepentahydrate (TMAOH.5H₂ O) dissolved in H₂ O. Orthophosphoric acid (85%H₃ PO₄)was then added to form a final reaction mixture having acomposition expressed in molar oxide ratios of:

    1.0TMAOH:1.0Ga.sub.2 O.sub.3 :1.0P.sub.2 O.sub.5 :40H.sub.2 O

The reaction mixture was divided into several portions. Each portion wassealed in stainless steel pressure vessels lined withpolytetrafluoroethylene and each portion heated in an oven at one of thefollowing: (a) 150° C. for 24 hours; (b) 150° C. for 96 hours; (c) 200°C. for 24 hours; and (d) 200° C. for 96 hours. The solid products from(a), (b), (c) and (d) were recovered by centrifugation, washed withwater, and dried in air at room temperature (18° C.-22° C.). Theresulting x-ray powder diffraction pattern of the product of eachpreparation corresponded to a product mixture, the major portion of eachbeing characterized by an x-ray powder diffraction pattern essentiallythe same as Table I, above, corresponding to GaPO₄ -a. The productmixture also contained gallium(III) hydroxide.

(b) SEM analysis of the solid product from preparation (d) of part (a),above, showed a large fraction of the sample to be crystals with ahexagonal prism morphology with lengths ranging up to 100 microns. EDAXspot probe analyses of these crystals are consistent with the presenceof both elements, Ga and P, in roughly equal amounts in the crystals.

(c) A portion of the solid from preparation (a) of part (a), above, wassubjected to DTA/TGA thermal analysis. Slow heatup (5° C./min.) inflowing air resulted in a strong, sharp exotherm accompanied tobreakdown, release, and combustion of the tetramethylammonium species(template) entrapped within the GaPO₄ -a gallophosphate molecular sieveframework structure as a result of its preparation.

EXAMPLE 3

(a) Using a procedure and reagents similar to that of Example 2, above,but with the use of an aqueous solution of 40 wt.% tetraethylammoniumhydroxide (TEAOH) instead of the tetramethylammonium hydroxide(TMAOH.5H₂ O), a reaction mixture was prepared having a chemicalcomposition in molar oxide ratios of:

    1.0TEAOH:1.0Ga.sub.2 O.sub.3 :1.0P.sub.2 O.sub.5 :40H.sub.2 O

A portion of this mixture was heated at 150° C. for 97 hours. Thisheating and subsequent solids recovery were by the methods described inExample 2. The major component of the product was GaPO₄ -a and wascharacterized by the x-ray powder diffraction pattern of Table I, above.As observed in Example 2, some of the gallium(III) hydroxide startingmaterial was present in the solid product. Chemical analysis of theproduct gave 54.6 wt.% Ga₂ O₃, 29.4 wt.% P₂ O₅, 8.2 wt.% Carbon, 1.2wt.% Nitrogen and 16.6 wt.% LOI. In terms of the components identifiedby the x-ray powder diffraction pattern, the analysis corresponds to amixture of 15.8 wt.% starting gallium(III) hydroxide expressed as Ga₂ O₃with the remaining 84.2 wt.% of the solid product being GaPO₄ -a havinga molar oxide ratio composition of:

    0.41TEAOH:1.0Ga.sub.2 O.sub.3 :1.0P.sub.2 O.sub.5 :0.72H.sub.2 O

which corresponds to the formula (anhydrous basis):

    0.10TEAOH:(Ga.sub.0.50 P.sub.0.50)O.sub.2

(b) Another portion of the reaction mixture of part (a) above wassimilarly heated at 150° C. for 24 hours. The x-ray pattern of theresulting solid also indicated it to be predominantely GaPO₄ -a in thepresence of some remaining gallium (III) hydroxide. A portion of thesample was placed under vacuum and heated from 25° to 300° C. at a 20degrees/min. and from 300° to 400° C. at 10 degrees/min. and held onehour at 400° C. before returning to room temperature. An x-ray patternwas then obtained of this vacuum calcined product which indicated thatthe GaPO₄ -a component of the sample remained essentially fullycrystalline, although some shifts of individual peak intensities andpositions resulted from the removal of entrapped species.

(c) The species GaPO₄ -a is a crystalline gallophosphate whose essentialframework structure has a chemical composition, expressed in terms ofmolar oxide ratios, of:

    Ga.sub.2 O.sub.3 :1±0.2P.sub.2 O.sub.5

All of the GaPO₄ -a compositions for which the x-ray powder diffractionpatterns have been obtained have a generalized x-ray diffraction as setforth in pattern Table II below:

                  TABLE II                                                        ______________________________________                                        2θ      d(A)      100 × (I/Io)                                    ______________________________________                                        8.1-8.3       10.9-10.6 100                                                   9.6-9.9       9.2-910   2-18                                                  10.4-10.6     8.52-8.38 1-38                                                  13.2-13.5     6.70-6.57 1-4                                                   14.1-14.4     6.28-6.17 1-9                                                   15.1-15.4     5.88-5.77 1-14                                                  16.3-16.6     5.42-5.33 2-6                                                   17.2-17.5     5.15-5.08 1-6                                                   17.6-18.0     5.03-4.94 1-13                                                  19.4-19.8     4.56-4.49 1-13                                                  21.8-22.0     4.08-4.03 7-15                                                  22.4-22.7     3.97-3.92 4-13                                                  24.2-24.5     3.68-3.63 1-3                                                   24.7-25.0     3.60-3.56 2-5                                                   27.1-27.2     3.29-3.28 1-6                                                   28.6-29.0     3.12-3.08 3-6                                                   29.2-29.5     3.05-3.03 1-3                                                   29.9-30.2     2.99-2.96 2-5                                                   30.4-30.8     2.94-2.90 1-7                                                   31.5-32.1     2.84-2.79 1-9                                                   33.2-33.4     2.70-2.69 1-3                                                   33.8          2.655-2.654                                                                             3-4                                                   35.0-35.1     2.564-2.557                                                                             0-1                                                   36.4          2.468-2.467                                                                             0-1                                                   36.8          2.442-2.440                                                                             0-1                                                   37.1          2.426-2.425                                                                             0-1                                                   38.4-38.6     2.346-2.334                                                                             0-2                                                   39.9-40.1     2.262-2.250                                                                             0-1                                                   42.0          2.151-2.150                                                                             0-1                                                   43.1-43.3     2.100-2.088                                                                             0-2                                                   44.0-44.3     2.059-2.046                                                                             0-1                                                   44.9-45.3     2.020-2.002                                                                             0-1                                                   45.6          1.991-1.990                                                                             0-1                                                   47.3-47.7     1.920-1.907                                                                             0-2                                                   48.0-48.3     1.897-1.883                                                                             0-2                                                   49.9-50.0     1.827-1.825                                                                             0-1                                                   51.2          1.785-1.782                                                                             0-1                                                   51.6-51.7     1.771-1.767                                                                             0-2                                                   53.2-53.5     1.723-1.713                                                                             0-1                                                   54.4          1.688-1.687                                                                             0-1                                                   ______________________________________                                    

A characteristic x-ray pattern for GaPO₄ -a contains at least thed-spacings set forth in Table A below:

                  TABLE A                                                         ______________________________________                                                                Relative                                              2.sup.θ  d(A)     Intensity                                             ______________________________________                                        8.1-8.3        10.9-10.6                                                                              VS                                                    9.6-9.9        9.2-9.0  VW-W                                                  10.4-10.6      8.52-8.38                                                                              VW-M                                                  15.1-15.4      5.88-5.77                                                                              VW-W                                                  21.8-22.0      4.08-4.03                                                                              VW-W                                                  22.4-22.7      3.97-3.92                                                                              VW-W                                                  ______________________________________                                    

EXAMPLE 4

(a) GaPO₄ -b was prepared by the followingprocedure: 7.2 grams ofgallium (III) sulfate hydrate (Ga₂ (SO₄)₃.12H₂ O) was dissolved in 8.7grams of H₂ O to which was added 2.6 grams of 85% orthophosphoric acid(H₃ PO₄). 11.1 grams of tri-n-propylamine (C₉ H₂₁ N) was added to thismixture to form a final reaction mixture having a composition in termsof molar oxide ratios of:

    7.0C.sub.9 H.sub.21 N:1.0Ga.sub.2 O.sub.3 :1.0P.sub.2 O.sub.5 :3.0H.sub.2 SO.sub.4 :60H.sub.2 O

A portion of the reaction mixture was placed in a sealed stainless steelpressure vessel lined with polytetrafluoroethylene and heated in an ovenat 150° C. for 24 hours. The solid product was recovered bycentrifugation and filtration. The solid product was water washed, anddried in air at room temperature. The product was well crystallized asshown by the x-ray powder diffraction pattern characterized by thefollowing data (Table III):

                  TABLE III                                                       ______________________________________                                        2.sup.θ d(A)    (I/Io) × 100                                      ______________________________________                                        7.4           11.96   100                                                     10.7          8.25    5                                                       13.1          6.79    2                                                       18.3          4.85    5                                                       21.5          4.13    8                                                       22.3          3.99    7                                                       22.7          3.92    1                                                       23.8          3.73    7                                                       24.8          3.60    4                                                       26.2          3.40    3                                                       29.2          3.06    10                                                      30.7          2.91    3                                                       31.1          2.88    1                                                       32.3          2.78    1                                                       32.6          2.75    1                                                       34.3          2.62    1                                                       36.5          2.461   1                                                       37.1          2.424   2                                                       37.7          2.386   1                                                       50.5          1.808   2                                                       ______________________________________                                    

A characteristic GaPO₄ -b x-ray pattern contains at least the d-spacingsset forth in Table B below:

                  TABLE B                                                         ______________________________________                                                              Relative                                                2.sup.θ  d(A)   Intensity                                               ______________________________________                                        7.4            12.0   VS                                                      18.2           4.85   W                                                       21.5           4.13   W                                                       22.3           3.99   W                                                       23.8           3.73   W                                                       29.2           3.06   W                                                       ______________________________________                                    

(b) A portion of the solid product described above was subjected toDTA/TGA thermal analysis. Slow heatup (10 deg. °C./min.) in flowing airresulted in a total weight loss by 650° C. of 14.3 wt.%. The first 6.5wt.% loss occurred in gradual dstages up to 390° C., apparentlyrepresenting loss of water and perhaps some tri-n-propylamine. Most ofthe remaining 7.8 wt.% loss occurred in a rapid step from 390° to 450°C. accompanied by a sharp, strong exotherm characteristic of breakdown,release, and combustion of the organic species (tri-n-propylamine)entrapped within the crystalline gallophosphate molecular sieveframework structure.

Chemical analysis of another portion of the same solid product found:49.4 wt.% Ga₂ O₃, 32.2 wt.% P₂ O₅, 0.89 wt.% Nitrogen, and 7.6 wt.%Carbon. This together with the 650° C. total loss of 14.3 wt.% from theabove thermal analysis, corresponds to a molar oxide ratio compositionof:

    0.07C.sub.9 H.sub.21 N:1.0Ga.sub.2 O.sub.3 :0.86P.sub.2 O.sub.5 :0.88H.sub.2 O

which is represented by the formula (anhydrous basis):

    0.07C.sub.9 H.sub.21 N:(Ga.sub.0.54 P.sub.0.46)O.sub.2

(c) Another portion of the reaction mixture described in part (a),above, was heated in an oven at 200° C. for 24 hours. The solid productwas isolated as described in Part (a), above. The x-ray powderdiffraction pattern indicated the product to consist principally of thequartz-like analog of gallium phosphate.

PROCESSES EMPLOYING GaPO₄ COMPOSITIONS

Among the hydrocarbon conversion reactions which may be catalyzed by theinstant gallophosphate compositions are cracking, hydrocracking,alkylation of both the aromatic and isoparaffin types, isomerizationincluding xylene isomerization, polymerization, reforming,hydrogenation, dehydrogenation, transalkylation, dealkylation andhydration.

Using gallophosphate catalyst compositions which contain a hydrogenationpromoter such as platinum or palladium, heavy petroleum residual stocks,cyclic stocks and other hydrocrackable charge stocks can be hydrocrackedat temperatures in the range of 400° F. to 825° F. using molar ratios ofhydrogen to hydrocarbon in the range of between 2 and 80, pressuresbetween 10 and 3500 p.s.i.g., and a liquid hourly space velocity (LHSV)of from 0.1 to 20, preferably 1.0 to 10.

The gallophosphate catalyst compositions employed in hydrocracking arealso suitable for use in reforming processes in which the hydrocarbonfeedstocks contact the catalyst at temperatures of from about 700° F. to1000° F., hydrogen pressures of from 100 to 500 p.s.i.g., LHSV values inthe range of 0.1 to 10 and hydrogen to hydrocarbon molar ratios in therange of 1 to 20, preferably between 4 and 12.

These same catalysts, i.e., those containing hydrogenation promoters,are also useful in hydroisomerization processes in which feedstocks suchas normal paraffins are converted to saturated branched chain isomers.Hydroisomerization is carried out at a temperature of from about 200° F.to 600° F., preferably 300° F. to 550° F. with an LHSV value of fromabout 0.2 to 1.0. Hydrogen is supplied to the reactor in admixture withthe hydrocarbon feedstock in molar proportions (H/Hc) of between 1 and5.

At somewhat higher temperatures, i.e., from about 650° F. to 1000° F.,preferably 850° F. to 950° F. and usually at somewhat lower pressureswithin the range of about 15 to 50 p.s.i.g., the same catalystcompositions are used to hydroisomerize normal paraffins. Preferably theparaffin feedstock comprises normal paraffins having a carbon numberrange of C₇ -C₂₀. Contact time between the feedstock and the catalyst isgenerally relatively short to avoid undesirable side reactions such asolefin polymerization and paraffin cracking. LHSV values in the range of0.1 to 10, preferably 1.0 to 6.0 are suitable.

The present gallophosphate catalysts may be employed in the conversionof alkylaromatic compounds, particularly the catalyticdisproportionation of toluene, ethylene, trimethyl benzenes, tetramethylbenzenes and the like. In the disproportionation process isomerizationand transalkylation can also occur. Group VIII noble metal adjuvantsalone or in conjunction with Group VI-B metals such as tungsten,molybdenum and chromium are preferably included in the catalystcomposition in amounts of from about 3 to 15 weight-% of the overallcomposition. Extraneous hydrogen can, but need not be present in theprocess. The process temperature is generally from about 400° to 750°0F. with pressures in the range of 100 to 2000 p.s.i.g. and LHSV valuesin the range of 0.1 to 15.

Catalytic cracking processes may be carried out with gallophosphatecompositions using feedstocks such as gas oils, heavy naphthas,deasphalted crude oil residua, etc. with gasoline being the principaldesired product. The process conditions employed for catalytic crackingprocesses are well known in the art. Temperature conditions of 850° to1100° F., LHSV values of 0.5 to 10 and pressure conditions of from about0 to 50 p.s.i.g. are typically employed.

Dehydrocyclization reactions employing paraffinic hydrocarbonfeedstocks, preferably normal paraffins having more than 6 carbon atoms,to form benzene, xylenes, toluene and the like are carried out usingessentially the same reaction conditions as for catalytic cracking. Forthese reactions it is preferred to use the gallophosphate catalystcompositions in conjunction with a Group VIII non-noble metal cationsuch as cobalt and nickel.

In catalytic dealkylation wherein it is desired to cleave paraffinicside chains from aromatic nuclei without substantially hydrogenating thering structure, relatively high temperatures in the range of about800°-1000° F. are employed at moderate hydrogen pressures of about300-1000 p.s.i.g., other conditions being similar to those describedabove for catalytic hydrocracking. Preferred catalysts are of the sametype described above in connection with catalytic dehydrocyclization.Particularly desirable dealkylation reactions include the conversion ofmethylnaphthalene to naphthalene and toluene and/or xylenes to benzene.

In catalytic hydrofining, the primary objective is to promote theselective hydrodecomposition of organic sulfur and/or nitrogen compoundsin the feed, without substantially affecting hydrocarbon moleculestherein. For this purpose it is preferred to employ the same generalconditions described above for catalytic hydrocracking, and catalysts ofthe same general nature described in connection with dehydrocyclizationoperations. Feedstocks include gasoline fractions, kerosenes, jet fuelfractions, diesel fractions, light and heavy gas oils, deasphalted crudeoil residua and the like any of which may contain up to about 5weight-percent of sulfur and up to about 3 weight-percent of nitrogen.

Similar conditions can be employed to effect hydrofining, i.e.,denitrogenation and desulfurization, of hydrocarbon feeds containingsubstantial proportions of organonitrogen and organosulfur compounds. Itis generally recognized that the presence of substantial amounts of suchconstituents markedly inhibits the activity of catalysts forhydrocracking. Consequently, it is necessary to operate at more extremeconditions when it is desired to obtain the same degree of hydrocrackingconversion per pass on a relatively nitrogenous feed than are requiredwith a feed containing less organonitrogen compounds. Consequently, theconditions under which denitrogenation, desulfurization and/orhydrocracking can be most expeditiously accomplished in any givensituation are necessarily determined in view of the characteristics ofthe feedstocks in particular the concentration of organonitrogencompounds in the feedstock.

The present gallophosphate compositions can be used in the sameconventional molecular sieving processes as heretofore have been carriedout using aluminosilicate or aluminophosphate molecular sieves. For usein these processes the gallophosphate compositions are preferablyactivated to remove any molecular species which may be present in theintracrystalline pore system as a result of synthesis or otherwise. Itis sometimes necessary to thermally destroy organic species present inas-synthesized gallophosphate compositions since some are too large tobe desorbed by conventional means.

The gallophosphate compositions are useful as adsorbents and are capableof separating mixtures of molecular species both on the basis ofmolecular size (kinetic diameters) and degree of polarity of theinvolved molecules. In the case of selective adsorption based onmolecular size, the gallophosphate adsorbent is chosen in view of thedimensions of its pores such that at least the smallest molecularspecies of the mixture can enter the intracrystalline void space whileat least the largest specie is excluded. In separations based on degreeof polarity, the more hydrophilic gallophosphate species willpreferentially adsorb the more polar molecular species of a mixturehaving different degrees of polarity even though both molecular speciescan enter the gallophosphate pore system.

What is claimed is:
 1. A process for converting a hydrocarbon comprisingcontacting the hydrocarbon under hydrocarbon converting conditions witha crystalline gallophosphate composition having a framework structurewhose chemical composition expressed in terms of mole ratios of oxidesis

    mR:Ga.sub.2 O.sub.3 :1.0±0.2P.sub.2 O.sub.5;

wherein "R" represents at least one organic templating agent present inthe intracrystalline pore system, "m" has a value of from 0.02 to 0.3and represents the moles of "R"; said framework structure beingmicroporous in which the pores have nominal diameters within the rangeof about 3 to about 10 Angstroms to give a hydroconverted product.
 2. Aprocess for convertoing a hydrocarbon comprising contacting thehydrocarbon under hydrocarbon converting conditions with a crystallinegallophosphate compositin having a framework structure whose chemicalcomposition expressed in terms of mole ratios of oxide is

    Ga.sub.2 O.sub.3 :1.0±0.2P.sub.2 O.sub.5 ;

characterized in that the framework structure is microporous, the poreshaving a nominal diameter within the range of about 3 to about 10Angstroms, and the framework structure retains at least 50 percent ofits crystallinity upon calcination at a temperature of at least 300° C.for at least one hour to give a hydroconverted product.
 3. Processaccording to claim 1 or 2 wherein the hydrocarbon conversion process iscracking.
 4. Process according to claim 1 or 2 wherein the hydrocarbonconversion process is hydrocracking.
 5. Process according to claim 1 or2 wherein the hydrocarbon conversion process is hydrogenation. 6.Process according to claim 1 or 2 wherein the hydrocarbon conversionprocess is polymerization.
 7. Process according to claim 1 or 2 whereinthe hydrocarbon conversion process is alkylation.
 8. Process accordingto claim 1 or 2 wherein the hydrocarbon conversion process is reforming.9. Process according to claim 1 or 2 wherein the hydrocarbon conversionprocess is hydrotreating.
 10. Process according to claim 1 or 2 whereinthe hydrocarbon conversion process is isomerization.
 11. Processaccording to claim 10 wherein the isomerization is xylene isomerization.